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Nutrients Oct 2022: Age-related macular degeneration (AMD) is a neurodegenerative ophthalmic disease. The purpose of this systematic review (SR) and meta-analysis was to evaluate if... (Meta-Analysis)
Meta-Analysis Review
: Age-related macular degeneration (AMD) is a neurodegenerative ophthalmic disease. The purpose of this systematic review (SR) and meta-analysis was to evaluate if dietary supplementation alone or in combinations might delay the progression of any of the stages of AMD. A SR and meta-analysis identifying cohort studies and randomized controlled trials (RCTs) evaluating the effect of supplements in patients diagnosed with AMD. PubMed, Scopus, Web of Science, CINAHL, and Cochrane were searched through 8th October 2021. Twenty studies, examining 5634 participants ranging from 55 to 80 years, were included in the SR. Eight studies were selected for meta-analysis (414 and 216 subjects in the intervention and control groups). Lutein and zeaxanthin plus -3 long-chain polyunsaturated fatty acids (-3 LC-PUFA) supplementation showed significant improvements in best-corrected visual acuity (BCVA) (SMD: -1.99, 95% CI: -3.33, -0.65) compared to the control group. Multifocal electroretinogram results (mfERG) were significantly improved overall (SMD: 4.59, 95% CI: 1.75, 7.43) after lutein plus zeaxanthin supplementation. Combinations of lutein and zeaxanthin with -3 LC-PUFA might be beneficial in preventing AMD progression and deterioration of visual function. Our results encourage initiating further studies with combinations of -3 LC-PUFA, lutein, and zeaxanthin especially in early AMD patients.
Topics: Humans; Zeaxanthins; Lutein; Xanthophylls; Visual Acuity; Double-Blind Method; Macular Degeneration; Dietary Supplements; Fatty Acids, Omega-3
PubMed: 36296956
DOI: 10.3390/nu14204273 -
The Cochrane Database of Systematic... Nov 2011Prostate cancer is a common cause of death in developed countries, yet the benefits of screening for prostate cancer still remain controversial. A prostate-specific... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Prostate cancer is a common cause of death in developed countries, yet the benefits of screening for prostate cancer still remain controversial. A prostate-specific antigen (PSA) test result greater than 4 ng/mL (nanograms/millilitre) has commonly been used as the cut-off level for seeking further tests to diagnose the presence (or absence) of prostate cancer. An increase in PSA levels may not necessarily be associated with an increased risk of prostate cancer, as PSA levels may also be increased in men with benign prostatic hyperplasia and prostatitis. Despite the uncertainty of the net benefit of early detection and treatment, safe and effective methods to prevent prostate cancer are of value. Consumers, seeking greater involvement in their healthcare, are increasingly turning to lifestyle modification and complementary and alternative medicines (CAMs) to maintain their health and prevent disease. Lycopene is a member of the carotenoid family, which is found abundantly in tomatoes, tomato-based products, strawberries, and watermelon. It has been hypothesised that lycopene is a strong antioxidant, which may lower the risk of cancer (including prostate cancer) in people who have diets rich in lycopene.
OBJECTIVES
To determine whether lycopene reduces the incidence of prostate cancer and prostate cancer-specific mortality. Secondary objectives include changes in PSA levels, prostate symptoms and the nature of adverse events associated with lycopene use.
SEARCH METHODS
Electronic searches were conducted across MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials (CENTRAL) databases. No language or other limitations were imposed.
SELECTION CRITERIA
Randomised controlled trials (RCTs) that investigated the use of lycopene for the prevention of prostate cancer were eligible for inclusion in this review.
DATA COLLECTION AND ANALYSIS
A search of electronic databases, performed in August 2011, identified 64 citations. All articles were selected for full-text review. From these citations, three studies were identified as meeting the inclusion criteria. Handsearching did not provide any additional studies.
MAIN RESULTS
Three RCTs, with a total of 154 participants were included in this review. None of the studies reported data on prostate cancer mortality. All of the included studies differed with respect to design, participants included and allocation of lycopene. This clinical heterogeneity limits the value on the pooled estimated of the meta-analyses. The methodological quality of two of the three included studies was assessed as posing a 'high' risk of bias. Meta-analysis indicated no statistical difference in PSA levels between men randomised to receive lycopene and the comparison group (MD (mean difference) -0.34, 95% CI (confidence interval) -2.01, 1.32). Only one study reported incidence of prostate cancer (10% in the lycopene group versus 30% in control group). The level of lycopene was also not statistically different in men randomised to receive lycopene and the comparison group (MD 0.39 µg/mL (micrograms/millilitre), 95% CI -0.19, 0.98). No other meta-analyses were possible since other outcomes assessed only had one study contributing data.
AUTHORS' CONCLUSIONS
Given that only three RCTs were included in this systematic review, and the high risk of bias in two of the three studies, there is insufficient evidence to either support, or refute, the use of lycopene for the prevention of prostate cancer. Similarly, there is no robust evidence from RCTs to identify the impact of lycopene consumption upon the incidence of prostate cancer, prostate symptoms, PSA levels or adverse events.
Topics: Anticarcinogenic Agents; Carotenoids; Humans; Lycopene; Male; Prostate-Specific Antigen; Prostatic Neoplasms; Randomized Controlled Trials as Topic
PubMed: 22071840
DOI: 10.1002/14651858.CD008007.pub2 -
Systematic Reviews Aug 2013Vitamins and minerals are essential for growth and metabolism. The World Health Organization estimates that more than 2 billion people are deficient in key vitamins and... (Review)
Review
BACKGROUND
Vitamins and minerals are essential for growth and metabolism. The World Health Organization estimates that more than 2 billion people are deficient in key vitamins and minerals. Groups most vulnerable to these micronutrient deficiencies are pregnant and lactating women and young children, given their increased demands. Food fortification is one of the strategies that has been used safely and effectively to prevent vitamin and mineral deficiencies.
METHODS
A comprehensive search was done to identify all available evidence for the impact of fortification interventions. Studies were included if food was fortified with a single, dual or multiple micronutrients and impact of fortification was analyzed on the health outcomes and relevant biochemical indicators of women and children. We performed a meta-analysis of outcomes using Review Manager Software version 5.1.
RESULTS
Our systematic review identified 201 studies that we reviewed for outcomes of relevance. Fortification for children showed significant impacts on increasing serum micronutrient concentrations. Hematologic markers also improved, including hemoglobin concentrations, which showed a significant rise when food was fortified with vitamin A, iron and multiple micronutrients. Fortification with zinc had no significant adverse impact on hemoglobin levels. Multiple micronutrient fortification showed non-significant impacts on height for age, weight for age and weight for height Z-scores, although they showed positive trends. The results for fortification in women showed that calcium and vitamin D fortification had significant impacts in the post-menopausal age group. Iron fortification led to a significant increase in serum ferritin and hemoglobin levels in women of reproductive age and pregnant women. Folate fortification significantly reduced the incidence of congenital abnormalities like neural tube defects without increasing the incidence of twinning. The number of studies pooled for zinc and multiple micronutrients for women were few, though the evidence suggested benefit. There was a dearth of evidence for the impact of fortification strategies on morbidity and mortality outcomes in women and children.
CONCLUSION
Fortification is potentially an effective strategy but evidence from the developing world is scarce. Programs need to assess the direct impact of fortification on morbidity and mortality.
Topics: Body Height; Body Weight; Child; Child Development; Female; Folic Acid; Food, Fortified; Humans; Iodine; Iron, Dietary; Micronutrients; Nutritional Status; Vitamin A; Vitamin D; Women's Health; Zinc
PubMed: 23971426
DOI: 10.1186/2046-4053-2-67 -
Nutrition Journal Sep 2013World Health Organization (WHO) guidelines recommend for children with severe acute malnutrition (SAM), high-dose vitamin A (VA) supplements be given on day 1 of... (Review)
Review
BACKGROUND
World Health Organization (WHO) guidelines recommend for children with severe acute malnutrition (SAM), high-dose vitamin A (VA) supplements be given on day 1 of admission, and on days 2 and 14 in the case of clinical signs of vitamin A deficiency (VAD). Daily low-dose VA follows, delivered in a premix added to F-75 and F-100. This study aimed to systematically review the evidence for safety and effectiveness of high-dose VA supplementation (VAS) in treatment of children with SAM.
METHODS
A comprehensive literature review was undertaken for all relevant randomized controlled trials (RCT) and observational studies from 1950 to 2012. Studies identified for full review were evaluated using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology using a set of pre-defined criteria: indirectness; inconsistency; imprecision; and study limitations. A quality rating of high, moderate, or low was then assigned to each study, and only those attaining moderate to high were considered in making recommendations.
RESULTS
Of the 2072 abstracts screened, 38 met criteria for full review, and 20 were rated moderate to high quality. Only one study replicated the WHO VA protocol in children with SAM. Indirectness was a critical limitation, as studies were not exclusive to children with SAM. There was inconsistency across trials for definitions of malnutrition, morbidities, and ages studied; and imprecision arising from sub-group analyses and small sample sizes. Evidence showed improved outcomes associated with low-dose compared to high-dose VAS, except in cases presenting with signs of VAD, measles, and severe diarrhea or shigellosis. Adverse outcomes related to respiratory infection, diarrhea, and growth were associated with high-dose VAS in children who were predominantly adequately nourished. No adverse effects of the high dose were found in children with SAM in the trial that replicated the WHO VA guideline.
CONCLUSION
This is the first systematic review of the safety and efficacy of high-dose VAS in treatment of SAM. We recommend a low-dose VAS regimen for children with SAM, except in cases presenting with measles, severe diarrhea (shigellosis), and any indication of VAD. Further research is needed in exclusively malnourished children and to explore alternate delivery strategies.
Topics: Child; Child Nutrition Disorders; Dietary Supplements; Dysentery, Bacillary; Evidence-Based Medicine; Humans; Malnutrition; Measles; Practice Guidelines as Topic; Precision Medicine; Severity of Illness Index; Vitamin A; Vitamin A Deficiency; World Health Organization
PubMed: 24028603
DOI: 10.1186/1475-2891-12-125 -
Nutrients Apr 2024This review aims to evaluate the efficacy of any vitamin administration(s) in preventing and managing COVID-19 and/or long-COVID. Databases were searched up to May 2023... (Meta-Analysis)
Meta-Analysis Review
The Efficacy of Multivitamin, Vitamin A, Vitamin B, Vitamin C, and Vitamin D Supplements in the Prevention and Management of COVID-19 and Long-COVID: An Updated Systematic Review and Meta-Analysis of Randomized Clinical Trials.
This review aims to evaluate the efficacy of any vitamin administration(s) in preventing and managing COVID-19 and/or long-COVID. Databases were searched up to May 2023 to identify randomized clinical trials comparing data on the effects of vitamin supplementation(s) versus placebo or standard of care on the two conditions of interest. Inverse-variance random-effects meta-analyses were conducted to estimate pooled risk ratios (RRs) and 95% confidence intervals (CIs) for all-cause mortality between supplemented and non-supplemented individuals. Overall, 37 articles were included: two regarded COVID-19 and long-COVID prevention and 35 records the COVID-19 management. The effects of vitamin D in preventing COVID-19 and long-COVID were contrasting. Similarly, no conclusion could be drawn on the efficacy of multivitamins, vitamin A, and vitamin B in COVID-19 management. A few positive findings were reported in some vitamin C trials but results were inconsistent in most outcomes, excluding all-cause mortality (RR = 0.84; 95% CI: 0.72-0.97). Vitamin D results were mixed in most aspects, including mortality, in which benefits were observed in regular administrations only (RR = 0.67; 95% CI: 0.49-0.91). Despite some benefits, results were mostly contradictory. Variety in recruitment and treatment protocols might explain this heterogeneity. Better-designed studies are needed to clarify these vitamins' potential effects against SARS-CoV-2.
Topics: Humans; Dietary Supplements; COVID-19; Vitamins; Vitamin D; Randomized Controlled Trials as Topic; Ascorbic Acid; SARS-CoV-2; Vitamin A; COVID-19 Drug Treatment; Vitamin B Complex
PubMed: 38732592
DOI: 10.3390/nu16091345 -
BMC Geriatrics Mar 2023Given their potent antioxidation properties, carotenoids play a role in delaying and preventing dementia and mild cognitive impairment (MCI). However, observational... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Given their potent antioxidation properties, carotenoids play a role in delaying and preventing dementia and mild cognitive impairment (MCI). However, observational studies have found inconsistent results regarding the associations between blood carotenoid levels and the risk of dementia and MCI. We conducted this systematic review and meta-analysis to investigate the relationship between blood carotenoid levels and the risk of dementia and MCI.
METHODS
A systematic search was performed in the Web of Science, PubMed, Embase, and Cochrane Library electronic databases to retrieve relevant English articles published from their inception until February 23, 2023. Study quality was assessed by the Newcastle-Ottawa scale. Standardized mean differences (SMDs) and 95% confidence intervals (CIs) were pooled using random-effect meta-analyses. Ultimately, 23 studies (n = 6610) involving 1422 patients with dementia, 435 patients with MCI, and 4753 controls were included.
RESULTS
Our meta-analysis showed that patients with dementia had lower blood lycopene (SMD: -0.521; 95%CI: -0.741, -0.301), α-carotene (SMD: -0.489; 95%CI: -0.697, -0.281), β-carotene (SMD: -0.476; 95%CI: -0.784, -0.168), lutein (SMD: -0.516; 95%CI: -0.753, -0.279), zeaxanthin (SMD: -0.571; 95%CI: -0.910, -0.232) and β-cryptoxanthin (SMD: -0.617; 95%CI: -0.953, -0.281) than the controls. Our results indicated that blood carotenoid levels were significantly lower in patients with dementia than in controls, despite high heterogeneity across the studies. Owing to insufficient data, we did not observe a similar and stable relationship between blood carotenoid levels and MCI.
CONCLUSIONS
Our meta-analysis indicated that lower blood carotenoid levels may be a risk factor for dementia and MCI.
Topics: Humans; Cognitive Dysfunction; Carotenoids; beta Carotene; Lutein; Dementia
PubMed: 36997905
DOI: 10.1186/s12877-023-03900-7 -
Hernia : the Journal of Hernias and... Aug 2014Despite the vast selection of brands available, nearly all synthetic meshes for hernia surgery continue to use one or other of three basic materials: polypropylene,... (Review)
Review
PURPOSE
Despite the vast selection of brands available, nearly all synthetic meshes for hernia surgery continue to use one or other of three basic materials: polypropylene, polyester and ePTFE. These are used in combination with each other or with a range of additional materials such as titanium, omega 3, monocryl, PVDF and hyaluronate. This systematic review of all experimental and clinical studies is aimed at investigating whether titanized meshes confer advantages over other synthetic meshes in hernia surgery.
MATERIALS AND METHODS
A search of the medical literature from 2002 to 2012, as indexed by Medline, was performed, using the PubMed search engine (http://www.pubmed.gov). The search terms were: hernia mesh, titanium coating, lightweight mesh, TiMesh, mesh complications. All papers were graded according to the Oxford hierarchy of evidence.
RESULTS
Patients operated on with the Lichtenstein technique performed using the lightweight titanium-coated mesh have a shorter convalescence than those with the heavy-weight mesh Prolene. For inguinal hernias operated on with the TAPP technique and using a lightweight titanium-coated mesh in comparison to a heavy-weight Prolene mesh, the early postoperative convalescence seems to improve. Titanized meshes do exhibit a negative effect on sperm motility 1 year after a TEP operation, but not after 3 years. The laparoscopic IPOM technique with a titanium-coated polypropylene mesh was associated with less postoperative pain in the short term, lower analgesic consumption and a quicker return to everyday activities compared with the Parietex composite mesh.
CONCLUSION
In clinical studies, the titanium-coated polypropylene mesh shows in inguinal hernia repair certain benefits compared with the use of older heavy-weight meshes.
Topics: Biocompatible Materials; Hernia, Inguinal; Herniorrhaphy; Humans; Polypropylenes; Surgical Mesh; Titanium
PubMed: 24253381
DOI: 10.1007/s10029-013-1187-3 -
Journal of Nutritional Science 2021Countries are increasingly transitioning from event-based vitamin A supplementation (VAS) distribution to delivery through routine health system contacts, shifting also... (Review)
Review
Countries are increasingly transitioning from event-based vitamin A supplementation (VAS) distribution to delivery through routine health system contacts, shifting also to administrative, electronic-based monitoring tools, a process that brings certain limitations affecting the quality of administrative VAS coverage. At present, there is no standardised methodology for measuring the coverage of VAS delivered through routine health services. To address this gap, we conducted a systematic review of the literature to identify and recommend methods to measure VAS coverage, with the aim of providing guidance to countries on the collection of consistent data for planning, monitoring and evaluating VAS programmes integrated into routine health systems. We searched the PubMed®, Embase®, Scopus, Google Scholar and World Health Organization (WHO) Global Index Medicus databases for studies published from 1 January 2000 to 1 January 2021, reporting original data on VAS coverage and methodologies used for measurement. We screened 2371 original titles and abstracts, assessed twenty-seven full-text articles and ultimately included eighteen studies. All but two studies used a coverage cluster survey (CCS) design to measure VAS coverage, adapting the WHO Vaccination Coverage Cluster Surveys methodology, by modifying sample size and sampling parameters. Annual two-dose VAS coverage was reported from only four studies. Until electronic-based systems to collect and analyse VAS data are equipped to measure routine two-dose VAS coverage using administrative data, CCSs that comply with the 2018 WHO Vaccination Coverage Cluster Surveys Reference Manual represent the gold-standard method for effective VAS programme monitoring.
Topics: Dietary Supplements; Humans; Surveys and Questionnaires; Vitamin A; Vitamin A Deficiency
PubMed: 34527226
DOI: 10.1017/jns.2021.65 -
Nutrition and Cancer 2014Cancer remains the second leading cause of death in the United States, and the number of cases is expected to continue to rise worldwide. Cancer prevention strategies... (Review)
Review
Cancer remains the second leading cause of death in the United States, and the number of cases is expected to continue to rise worldwide. Cancer prevention strategies are crucial for reducing the cancer burden. The carcinogenic potential of dietary acrylamide exposure from cooked foods is unknown. Acrylamide is a by-product of the common Maillard reaction where reducing sugars (i.e., fructose and glucose) react with the amino acid, asparagine. Based on the evidence of acrylamide carcinogenicity in animals, the International Agency for Research on Cancer has classified acrylamide as a group 2A carcinogen for humans. Since the discovery of acrylamide in foods in 2002, a number of studies have explored its potential as a human carcinogen. This article outlines a systematic review of dietary acrylamide and human cancer, acrylamide exposure and internal dose, exposure assessment methods in the epidemiologic studies, existing data gaps, and future directions. A majority of the studies reported no statistically significant association between dietary acrylamide intake and various cancers, and few studies reported increased risk for renal, endometrial, and ovarian cancers; however, the exposure assessment has been inadequate leading to potential misclassification or underestimation of exposure. Future studies with improved dietary acrylamide exposure assessment are encouraged.
Topics: Acrylamide; Animals; Carcinogens; Diet; Disease Models, Animal; Dose-Response Relationship, Drug; Epidemiologic Studies; Evidence-Based Practice; Female; Humans; Male; Neoplasms; alpha-Tocopherol; beta Carotene
PubMed: 24875401
DOI: 10.1080/01635581.2014.916323 -
The Cochrane Database of Systematic... May 2016Miscarriage is a common complication of pregnancy that can be caused by a wide range of factors. Poor dietary intake of vitamins has been associated with an increased... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Miscarriage is a common complication of pregnancy that can be caused by a wide range of factors. Poor dietary intake of vitamins has been associated with an increased risk of miscarriage, therefore supplementing women with vitamins either prior to or in early pregnancy may help prevent miscarriage.
OBJECTIVES
The objectives of this review were to determine the effectiveness and safety of any vitamin supplementation, on the risk of spontaneous miscarriage.
SEARCH METHODS
We searched the Cochrane Pregnancy and Childbirth Group Trials Register (6 November 2015) and reference lists of retrieved studies.
SELECTION CRITERIA
All randomised and quasi-randomised trials comparing supplementation during pregnancy with one or more vitamins with either placebo, other vitamins, no vitamins or other interventions. We have included supplementation that started prior to conception, periconceptionally or in early pregnancy (less than 20 weeks' gestation).
DATA COLLECTION AND ANALYSIS
Three review authors independently assessed trials for inclusion, extracted data and assessed trial quality. We assessed the quality of the evidence using the GRADE approach. The quality of evidence is included for numerical results of outcomes included in the 'Summary of findings' tables.
MAIN RESULTS
We included a total of 40 trials (involving 276,820 women and 278,413 pregnancies) assessing supplementation with any vitamin(s) starting prior to 20 weeks' gestation and reporting at least one primary outcome that was eligible for the review. Eight trials were cluster-randomised and contributed data for 217,726 women and 219,267 pregnancies in total.Approximately half of the included trials were assessed to have a low risk of bias for both random sequence generation and adequate concealment of participants to treatment and control groups. Vitamin C supplementation There was no difference in the risk of total fetal loss (risk ratio (RR) 1.14, 95% confidence interval (CI) 0.92 to 1.40, seven trials, 18,949 women; high-quality evidence); early or late miscarriage (RR 0.90, 95% CI 0.65 to 1.26, four trials, 13,346 women; moderate-quality evidence); stillbirth (RR 1.31, 95% CI 0.97 to 1.76, seven trials, 21,442 women; moderate-quality evidence) or adverse effects of vitamin supplementation (RR 1.16, 95% CI 0.39 to 3.41, one trial, 739 women; moderate-quality evidence) between women receiving vitamin C with vitamin E compared with placebo or no vitamin C groups. No clear differences were seen in the risk of total fetal loss or miscarriage between women receiving any other combination of vitamin C compared with placebo or no vitamin C groups. Vitamin A supplementation No difference was found in the risk of total fetal loss (RR 1.01, 95% CI 0.61 to 1.66, three trials, 1640 women; low-quality evidence); early or late miscarriage (RR 0.86, 95% CI 0.46 to 1.62, two trials, 1397 women; low-quality evidence) or stillbirth (RR 1.29, 95% CI 0.57 to 2.91, three trials, 1640 women; low-quality evidence) between women receiving vitamin A plus iron and folate compared with placebo or no vitamin A groups. There was no evidence of differences in the risk of total fetal loss or miscarriage between women receiving any other combination of vitamin A compared with placebo or no vitamin A groups. Multivitamin supplementation There was evidence of a decrease in the risk for stillbirth among women receiving multivitamins plus iron and folic acid compared iron and folate only groups (RR 0.92, 95% CI 0.85 to 0.99, 10 trials, 79,851 women; high-quality evidence). Although total fetal loss was lower in women who were given multivitamins without folic acid (RR 0.49, 95% CI 0.34 to 0.70, one trial, 907 women); and multivitamins with or without vitamin A (RR 0.60, 95% CI 0.39 to 0.92, one trial, 1074 women), these findings included one trial each with small numbers of women involved. Also, they include studies where the comparison groups included women receiving either vitamin A or placebo, and thus require caution in interpretation.We found no difference in the risk of total fetal loss (RR 0.96, 95% CI 0.93 to 1.00, 10 trials, 94,948 women; high-quality evidence) or early or late miscarriage (RR 0.98, 95% CI 0.94 to 1.03, 10 trials, 94,948 women; moderate-quality evidence) between women receiving multivitamins plus iron and folic acid compared with iron and folate only groups.There was no evidence of differences in the risk of total fetal loss or miscarriage between women receiving any other combination of multivitamins compared with placebo, folic acid or vitamin A groups. Folic acid supplementation There was no evidence of any difference in the risk of total fetal loss, early or late miscarriage, stillbirth or congenital malformations between women supplemented with folic acid with or without multivitamins and/or iron compared with no folic acid groups. Antioxidant vitamins supplementation There was no evidence of differences in early or late miscarriage between women given antioxidant compared with the low antioxidant group (RR 1.12, 95% CI 0.24 to 5.29, one trial, 110 women).
AUTHORS' CONCLUSIONS
Taking any vitamin supplements prior to pregnancy or in early pregnancy does not prevent women experiencing miscarriage. However, evidence showed that women receiving multivitamins plus iron and folic acid had reduced risk for stillbirth. There is insufficient evidence to examine the effects of different combinations of vitamins on miscarriage and miscarriage-related outcomes.
Topics: Abortion, Habitual; Abortion, Spontaneous; Antioxidants; Ascorbic Acid; Dietary Supplements; Female; Folic Acid; Humans; Iron; Pre-Eclampsia; Pregnancy; Pregnancy Outcome; Pregnancy, Multiple; Prenatal Care; Randomized Controlled Trials as Topic; Stillbirth; Vitamin A; Vitamins
PubMed: 27150280
DOI: 10.1002/14651858.CD004073.pub4